New York state has yanked the medical license of an elusive radiologist whose interpretations of X-rays, MRIs and ultrasound tests posed an “imminent danger” to the public, The Post has learned.

Officials said Dr. Michael Martin Katz failed to diagnose serious ailments in some cases, and found non-existent problems in other cases.

In an unusual action, the state last month suspended Katz’s license immediately, before holding a disciplinary hearing. In most cases, doctors accused of misconduct are allowed to continue practicing until the hearing process and all appeals are completed.

“Based on our investigation, the doctor has made such egregious lapses that his continued practice could put additional patients at risk,” said Kristine Smith, a spokeswoman for the state Board for Professional Medical Conduct.

“We felt the potential for patients to be seriously harmed was definitely there,” she said.

The state medical board also accused Katz, 52, of failing to keep records of his work, doctoring a report to cover up a misdiagnosis and lying about his credentials.

The doctor “intended to deceive,” the board charged.

The rarely-seen radiologist – who was barred from the state Medicaid program 10 years ago for “unacceptable practices” – is known for his “voluminous” billings under the state’s no-fault auto-insurance system, insurance-company investigators told The Post.

Katz is the focus of several probes and lawsuits by insurance companies, which are under state pressure to fight the rampant fraud and abuse that have driven up auto-insurance costs.

New York rates are now the second highest in the nation.

Katz and a series of companies he has owned have billed millions of dollars for magnetic resonance imaging (MRI), X-rays and ultrasound testing in clinics from The Bronx to Staten Island, from Yonkers to Long Island, and across the Hudson, industry sources said.

Much of the lucrative testing was done with MRI units in trailers that move from clinic to clinic. Under state law, Katz didn’t have to be present for the tests, which are conducted by technicians who don’t have to be licensed.

Katz was charged with “gross negligence,” “gross incompetence,” “practicing fraudulently,” and “excessive testing” by the state medical board.

In its disciplinary charges, the board accused Katz of overlooking serious conditions in MRIs, including a brain tumor, scoliosis and herniated discs.

In many other cases, the board charged, Katz diagnosed herniated discs that didn’t exist.

He also ordered ultrasound exams of the spine – a procedure widely debunked in the medical profession as worthless.

Board officials told The Post that Katz’s diagnoses of non-existent problems could not only fuel fraudulent billing for medical care, but also could subject patients to needless surgery or other unnecessary treatment.

On his reports, Katz “knowingly and falsely” identified himself as a FACR, a Fellow of the American College of Radiology, the state charged.

The 32,000-member American College of Radiology says only about 100 radiologists who make “significant contributions” to the field are elected fellows each year.

“This is a position of honor and distinction, and people shouldn’t be saying they are fellows if they haven’t earned it,” said ACR spokesman Michael Bernstein.

Katz did not return calls from The Post, and he could not be reached at his home in Hewlett, L.I., or at a number of offices and clinics where he has worked. But two of his lawyers said he denies any wrongdoing and maintains he’s being attacked unfairly.

The doctor “adamantly denies” the state’s accusations “and is preparing a vigorous defense,” said lawyer John Tasolides of Jericho, L.I.

Katz considers the state charges “frivolous” and “political” and motivated by insurance companies to “ruin his career and reputation,” Tasolides said.

“They’re trying to put him out of business,” said another lawyer, Joseph Henig of Bellmore, L.I.

“He’s making a lot of money, evidently, and this hurts the insurance companies no matter what the windfall profits they show at the end of the year. This guy is being persecuted unjustly,” Henig said.

Katz’s troubles are mounting.

Last week, he was accused of engaging in the “sham ownership” of two New Jersey diagnostic companies that perform MRI tests in mobile units that park outside chiropractors’ offices.

In a suit filed in Monmouth County Superior Court, the Prudential insurance company charged that Katz and another doctor lent their licenses – and funneled money – to businessmen who illegally controlled both the finances and medical operations of the clinics. In New Jersey, as in New York, only doctors can own and operate medical practices.

The “entrepreneurs” running the clinics charged about $1,000 for each MRI, of which they gave Katz $50, according to the suit.

Katz has ignored two court orders to testify in the case, the suit said. His lawyer in the suit, Brian Fowler of Hackensack, N.J., said he could not comment because he had just taken the case and had not spoken to Katz.

Katz is also fighting a ruling by a New York arbitrator who last year found the radiologist was engaged in a scheme of “illegal referrals” and “manipulation” of MRI reports to help other medical providers run up bills for “extensive” tests and treatment of bogus injuries.

In one case, Katz found a torn knee cartilage “where there was none” – allowing a medical clinic to justify treating the patient for more than five months, arbitrator John Funches said.

“In fact, no treatment was required because the knee was normal and had not been injured in the patient’s auto accident,” Funches concluded.

Katz counterattacked in a suit filed last week, contending that Funches is biased against him and in cahoots with the insurance company’s lawyer.

Katz’s suit complains that the hearing was held in his absence even after he withdrew his bid to be paid $1,600 for two MRIs that insurers had called “medically unnecessary.”

Katz claims he never got the subpoena ordering him to show up for the hearing.

Katz is listed in state records as the owner or shareholder of 18 medical corporations in New York and several in New Jersey.

Many of the corporations are listed at the address of a home he recently sold in Lido Beach, L.I.

Katz and his wife, Margery, also have a fleet of cars registered at that address, including convertible Jaguars, Mercedes Benzes and Jeeps.

Other business addresses are simply mail drops, including a mailbox in a Brooklyn apartment building.

Insurance-company investigators said Katz has billed for radiology exams on behalf of at least 27 clinics in recent years.

According to figures from just one insurance company, three of Katz’s New York corporations – Ocean Diagnostic Radiology, Junction Diagnostic Radiology and Ultra Diagnostic Radiology – billed for more than 7,900 MRIs and other exams stemming from 2,700 no-fault claims over the past six years.

The total tab: $6.5 million.

When The Post checked out an address for Ocean Diagnostic, it turned out to be a second-floor office in a dingy apartment building on Avenue X in Brooklyn.

“We haven’t worked with Dr. Katz in two years. We have nothing to do with him,” said a man who identified himself only as Eddie, the manager.

Asked why there were two plaques on the wall with medical certificates bearing the name “Michael Martin Katz,” Eddie replied: “The documentation, the documentation.”

He refused to answer further questions.

At the Williamsburg address of another of Katz’s companies, Dan Gilmore identified himself as the “billing administrator” for Katz and several other doctors. He said Katz had come in recently to report that his license had been suspended.

Tasolides, the lawyer, denied that Katz has interpreted an inordinate number of radiology films.

“During the last three years, Dr. Katz has on average not read more than 60 MRIs per week,” he said.

Tasolides said Katz owns no MRI facilities and had set up professional corporations “to more easily administer billing and record-keeping.”

Katz and several radiologists who joined his corporations have “never actively practiced medicine through more than a few professional corporations at a time,” he said.

Some of Katz’s corporations have remained open only to collect payments “because the insurance companies take years to resolve and pay claims,” Tasolides said.